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No. 748,609. PATENTED JAN. 5, 1904* F. F. HUNT. PRODUCTION OF HYDROXID$ AND oxms OPMETALS BY ELEGTROLYSIS.

APYLIOATION FILED JAN. 22. 1903.,

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- UNITED STATES Patented January 5, 1904.

PATENT OFFICE.

FREDERICK F. HUNT, OF NEW BRIGHTON, NEW YORK, ASSIGNOR OF TWO- THIRDS TO MAAS & WALDSTEIN, OF NEW YORK, N. Y., A FIRM.

PRODUCTION OF HYDROXIDS AND OXIDS 0F METALS BY ELECTROLYSIS.

SPECIFICATION forming part of Letters Patent No. 748,609, dated January 5, 1904. Application filed January 22, 1903. Serial No. 140,118. (No specimens.)

To all whom it may concern:

Be it known that I, FREDERICK F. HUNT, a subject of the King-of England, and a resident of New Brighton, Staten Island, State of New York, have invented certain new and useful Improvements in the Production of Hydroxids and Oxids of Metals by Electrolysis, of which the following is a specification.

This invention relates to a new and useful process whereby the hydroxids and oxids of the various metals may be produced by electrolysis as separate bodies for use in the arts.

In carrying out the process both electrodes are formed of the same metal and that metal. is selected Whose hydroxid or oxid is desired. A suitable electrolyte is employed consisting, preferably, of a neutral solution and of an alkali or alkaline earth whose acid radical will form a salt of the metal of the anode which is soluble in the electrolyte. Each electrode is alternately made the anode and the cathode at suitable intervals, and the current is passed through the electrolyte. As a result of these steps the metal which constitutes the anode for the time being is dissolved and the hydroxid or oxid thereof is formed and precipitated. This reversal of the polarity of the electrodes may be effected either by reversing the current or byrevers ing the position and circuit connections of the electrodes or in any other suitableway and is an important and essential feature of this invent-ion. If an attempt were made to produce hydroxids or oxids of the metals by electrolysis without reversing the polarity of the electrodes, such an obstructive condition of the cathode, whether formed of the same metal as the anode or not, would be induced as to materially interfere with the proper passage of the electric current. This condition of the cathode would produce a resistance which would gradually increase to such a degree as to make prohibitive the commercial production of the hydroxids and oxids of the metals. However, by forming both electrodes of the same metal and then reversing their polarity at suitable intervals the production of the hydroxids and oxids of the metals may be successfully and economically carried out in accordance with this invention. It requires a perceptible interval ter or in neutral salt solutions.

of time to produce this obstructive condition of the cathode, and this interval varies with the different metals employed as the anodes and cathodes and also with the diiferent elect-rolytes employed. It would also vary with the current density and, perhaps, with the temperature of the electrolyte. This interval, however, can be readily determined by trial for any electrolyte and for any metal in that electrolyte. Then by alternately reversing the polarity of the electrodes at shorter intervals of time than is required to produce this obstructive condition of the cathode a proper flow of the current is ob 'tained, and the process can be carried on continuously, successfully, and economically.

In the accompanying drawing, forming part of this specification, is shown a simple form of an electrolytic apparatus by means of which the process may be carried out. i

1 is the vessel containing an electr olyte, in which is inserted the electrodes 2 and 3, connected by circuit-wires 4 and 5 with the generator 6.

7 is a switch interposed in the circuit by means of which the current may be reversed through the electrolyte, so as to alternately change the polarity of the electrodes at suitable intervals.

The process of course is not restricted to the employment of any particular character of apparatus. The means for reversing the current may operate by hand or automatically and may operate as rapidly as may be found convenient or desirable.

The process may be carried out with any of the metals acting as the anode and cathode alternately which does not decompose in wa- The hydroxids or oxids obtained may be converted into any salt desired by treating them with the acid corresponding to the salt desired. For example, given the hydroxid of copper the sulfate of copper may be produced therefrom by the addition of sufuric acid, as follows:

The hydroxids of the metals obtained may be converted into the corresponding oxids by simply drying and heating and may be also converted into the higher oxids by suitable radical of the salt of the electrolyte.

treatment-as, for example, treating them with an oxidizing agent.

In carrying out the process in connection with one class of metals the hydroxids will be at once produced. Zinc, copper, iron, antimony, 850., belong to this class. Hydroxids will in all cases be thus produced, except where the anode consists of a metal of which there is no hydroxid. In such cases oxids instead of hydroxids will be produced. Silver and some of the other precious metals be-' long to the class of metals of which no hydroxids exist and where oxids will therefore be produced by the process.

I will now describe more particularly What I understand to be the chemical reactions which take place during the process. The passage of the current through the electrolyte primarily decomposes into its constituent parts, the salt solution acting as the electrolyte. One of these constituentparts-namely, the acid radical of this salt-acts upon the metal of the anode and produces soluble salts of this metal, whose acid radical is the acid The other of these constituent parts so producednamely, the metallic base of the salt of the electrolytecomes in contact with the water and acts to form the hydroxid of this alkaline metal. This alkaline hydroxid so produced then reacts with the salt of the anode metal and produces the hydroxid or oxid of such metal and also produces the same alkaline salt used in the electrolyte. The hydroxid or oxid of the anode metal so produced, which is the body desired, forms as a precipitate.

The following chemical equations illustrate the supposed reactions in the production of an hydroxid, taking tin as the metal of the electrodes and chlorid of sodium as the alkaline salt of the electrolyte:

The metallic sodium thus formed coming in contact with the water of the electrolyte produces sodium hydroxid, as follows:

Na+H O=NaHO+H. The sodium hydroxid then reacts upon the chlorid of tin, precipitating tin hydroxid and reforming chlorid of sodium, as follows:

Ag+NaNO =AgNO +Na The metallic sodium thus formed coming into contact with the water of the electrolyte produces sodium hydroxid, as follows:

Na+H O=NaHO+H.

The sodium hydroxid then reacts upon the nitrate of silver, precipitating the silver oxid and reforming nitrate of sodium, as follows:

The mere carrying out of the process is not dependent upon any particular temperature or strength of the electrolyte nor upon any particular electric current density; but for the most economical results these details could readily be determined by trial for the different metals and electrolytes. In general a warmed electrolyte will be found advantageous. In producing the hydroxid of tin a five-per-cent. to ten-per-cent. solution of sodium chlorid at a temperature between 30 and 40 centigrade and an electric current density of from twelve to fifteen amperes per square foot of anode at about two and onehalf volts and with a reversal of the polarity of the electrodes at intervals of about one minute is recommended.

After the hydroxids and oxids have been electrolytically produced as above described they are then collected and amassed as separate bodies apart from the electrodes for use in the arts.

What I claim as my invention, and desire to secure by Letters Patent, is

1. In the production by electrolysis of the hydroxids and oxids of the metals as separate bodies for use in the arts, the process which consists in passing a current of electricity through a suitable electrolyte having both the electrodes formed of the metal whose hydroxid or oxid is desired, and making each electrode the anode and the cathode, alternately, at suitable intervals, and thereafter collecting and amassing said hydroxids and oxids as separate bodies apart from the electrodes.

2. In the production by electrolysis of the hydroxids and oxids of the metals as separate bodies for use in the arts, the process which consists in passing a current of electricity through a suitable electrolyte having both the electrodes formed of the metal whose hydroxid or oxid is desired, and making each electrode the anode and the cathode, alternately, at'suitable intervals, said electrolyte consisting of a neutral-salt solu tion,and thereafter collecting and amassing said hydroxids and oxids as separate bodies apart from the electrodes.

3. In the production by electrolysis of the hydroxids and oxids of the metals as separate bodies for use in the arts, the process which consists in passing a current of electricity through a suitable electrolyte having both the electrodes formed'of the metal whose hydroxid or oxid is desired, and making each electrode the anode and the cathode, alternately, at suitable intervals, said electrolyte consisting of a neutral-salt solution of an alkali or alkaline earth whose acid radical will combine with the metal of the anode to form a salt of that metal which is soluble in the solution.

4. In the production by electrolysis of the hydroxids and oxids of the metals as separate bodies for use in the arts, the process which consists in passing a current of electricity through a suitable electrolyte having both the electrodes formed of the metal whose hydroxid or oxid is desired, and making each electrode the anode and the cathode, alternately, at suitable intervals, said electrolyte consisting of a neutral-salt solution of an alkali or alkaline earth whose acid radical will combine with the metal of the anode to form a salt of that metal which is soluble in the solution, and thereby also forming a hydroxid of the base of the salt of the electrolyte, which hydroxid thus produced and which metal salt thus produced react to form the hydroxid or oxid of the metal of the anode desired and also to form the same alkaline salt used in the electrolyte.

5. In the production by electrolysis of the hydroxids and oxids of tin, the process which consists in passing an electric current through a suitable electrolyte having both the electrodes formed of tin and making each electrode the anode and the cathode, alternately, at suitable intervals, said electrolyte consisting of a neutral-salt solution whose acid radical will combine with the tin to form a tin salt soluble in the solution. a 6. In the production by electrolysis of the hydroxids and oxids of tin, the process which consistsin passing an electric current through an electrolyte having both the electrodes formed of tin and making each electrode the anode and the cathode, alternately, at suitable intervals, said electrolyte consisting of a solution of common salt.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

FREDERICK F. HUNT.

Witnesses:

NICHOLAS M. GOODLETI, J r., FRANK J. MCBARRON. 

